/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  FIPS-180-2 compliant SHA-256 implementation
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 *  The SHA-256 Secure Hash Standard was published by NIST in 2002.
 *
 *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
 */

#include "tls/config.h"

#if defined(MBEDTLS_SHA256_C)

#include "tls/sha256.h"

#include <string.h>

#if defined(MBEDTLS_SELF_TEST)
#if defined(MBEDTLS_PLATFORM_C)
#include "tls/platform.h"
#else
#include <stdio.h>
#include <stdlib.h>
#define mbedtls_printf printf
#define mbedtls_calloc    calloc
#define mbedtls_free       free
#endif							/* MBEDTLS_PLATFORM_C */
#endif							/* MBEDTLS_SELF_TEST */

#if !defined(MBEDTLS_SHA256_ALT)

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
	volatile unsigned char *p = v;
	while (n--) {
		*p++ = 0;
	}
}

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n, b, i)                            \
do {                                                    \
(n) = ((uint32_t)(b)[(i)] << 24)             \
| ((uint32_t)(b)[(i) + 1] << 16)             \
| ((uint32_t)(b)[(i) + 2] <<  8)             \
| ((uint32_t)(b)[(i) + 3]);            \
} while (0)
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n, b, i)                            \
do {                                                    \
(b)[(i)] = (unsigned char)((n) >> 24);       \
(b)[(i) + 1] = (unsigned char)((n) >> 16);       \
(b)[(i) + 2] = (unsigned char)((n) >>  8);       \
(b)[(i) + 3] = (unsigned char)((n));       \
} while (0)
#endif

void mbedtls_sha256_init(mbedtls_sha256_context *ctx)
{
	memset(ctx, 0, sizeof(mbedtls_sha256_context));
}

void mbedtls_sha256_free(mbedtls_sha256_context *ctx)
{
	if (ctx == NULL) {
		return;
	}

	mbedtls_zeroize(ctx, sizeof(mbedtls_sha256_context));
}

void mbedtls_sha256_clone(mbedtls_sha256_context *dst, const mbedtls_sha256_context *src)
{
	*dst = *src;
}

/*
 * SHA-256 context setup
 */
void mbedtls_sha256_starts(mbedtls_sha256_context *ctx, int is224)
{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	if (is224 == 0) {
		/* SHA-256 */
		ctx->state[0] = 0x6A09E667;
		ctx->state[1] = 0xBB67AE85;
		ctx->state[2] = 0x3C6EF372;
		ctx->state[3] = 0xA54FF53A;
		ctx->state[4] = 0x510E527F;
		ctx->state[5] = 0x9B05688C;
		ctx->state[6] = 0x1F83D9AB;
		ctx->state[7] = 0x5BE0CD19;
	} else {
		/* SHA-224 */
		ctx->state[0] = 0xC1059ED8;
		ctx->state[1] = 0x367CD507;
		ctx->state[2] = 0x3070DD17;
		ctx->state[3] = 0xF70E5939;
		ctx->state[4] = 0xFFC00B31;
		ctx->state[5] = 0x68581511;
		ctx->state[6] = 0x64F98FA7;
		ctx->state[7] = 0xBEFA4FA4;
	}

	ctx->is224 = is224;
}

#if !defined(MBEDTLS_SHA256_PROCESS_ALT)
static const uint32_t K[] = {
	0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
	0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5,
	0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
	0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174,
	0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC,
	0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
	0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7,
	0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967,
	0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
	0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85,
	0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3,
	0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
	0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5,
	0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3,
	0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
	0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
};

#define  SHR(x, n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x, n) (SHR(x, n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^  SHR(x, 3))
#define S1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^  SHR(x, 10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))

#define F0(x, y, z) ((x & y) | (z & (x | y)))
#define F1(x, y, z) (z ^ (x & (y ^ z)))

#define R(t)                                    \
(                                               \
W[t] = S1(W[t -  2]) + W[t -  7] +          \
S0(W[t - 15]) + W[t - 16]            \
)

#define P(a, b, c, d, e, f, g, h, x, K)                  \
{                                               \
temp1 = h + S3(e) + F1(e, f, g) + K + x;      \
temp2 = S2(a) + F0(a, b, c);                  \
d += temp1; h = temp1 + temp2;              \
}

void mbedtls_sha256_process(mbedtls_sha256_context *ctx, const unsigned char data[64])
{
	uint32_t temp1, temp2, W[64];
	uint32_t A[8];
	unsigned int i;

	for (i = 0; i < 8; i++) {
		A[i] = ctx->state[i];
	}

#if defined(MBEDTLS_SHA256_SMALLER)
	for (i = 0; i < 64; i++) {
		if (i < 16) {
			GET_UINT32_BE(W[i], data, 4 * i);
		} else {
			R(i);
		}

		P(A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i], K[i]);

		temp1 = A[7];
		A[7] = A[6];
		A[6] = A[5];
		A[5] = A[4];
		A[4] = A[3];
		A[3] = A[2];
		A[2] = A[1];
		A[1] = A[0];
		A[0] = temp1;
	}
#else							/* MBEDTLS_SHA256_SMALLER */
	for (i = 0; i < 16; i++) {
		GET_UINT32_BE(W[i], data, 4 * i);
	}

	for (i = 0; i < 16; i += 8) {
		P(A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i + 0], K[i + 0]);
		P(A[7], A[0], A[1], A[2], A[3], A[4], A[5], A[6], W[i + 1], K[i + 1]);
		P(A[6], A[7], A[0], A[1], A[2], A[3], A[4], A[5], W[i + 2], K[i + 2]);
		P(A[5], A[6], A[7], A[0], A[1], A[2], A[3], A[4], W[i + 3], K[i + 3]);
		P(A[4], A[5], A[6], A[7], A[0], A[1], A[2], A[3], W[i + 4], K[i + 4]);
		P(A[3], A[4], A[5], A[6], A[7], A[0], A[1], A[2], W[i + 5], K[i + 5]);
		P(A[2], A[3], A[4], A[5], A[6], A[7], A[0], A[1], W[i + 6], K[i + 6]);
		P(A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[0], W[i + 7], K[i + 7]);
	}

	for (i = 16; i < 64; i += 8) {
		P(A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], R(i + 0), K[i + 0]);
		P(A[7], A[0], A[1], A[2], A[3], A[4], A[5], A[6], R(i + 1), K[i + 1]);
		P(A[6], A[7], A[0], A[1], A[2], A[3], A[4], A[5], R(i + 2), K[i + 2]);
		P(A[5], A[6], A[7], A[0], A[1], A[2], A[3], A[4], R(i + 3), K[i + 3]);
		P(A[4], A[5], A[6], A[7], A[0], A[1], A[2], A[3], R(i + 4), K[i + 4]);
		P(A[3], A[4], A[5], A[6], A[7], A[0], A[1], A[2], R(i + 5), K[i + 5]);
		P(A[2], A[3], A[4], A[5], A[6], A[7], A[0], A[1], R(i + 6), K[i + 6]);
		P(A[1], A[2], A[3], A[4], A[5], A[6], A[7], A[0], R(i + 7), K[i + 7]);
	}
#endif							/* MBEDTLS_SHA256_SMALLER */

	for (i = 0; i < 8; i++) {
		ctx->state[i] += A[i];
	}
}
#endif							/* !MBEDTLS_SHA256_PROCESS_ALT */

/*
 * SHA-256 process buffer
 */
void mbedtls_sha256_update(mbedtls_sha256_context *ctx, const unsigned char *input, size_t ilen)
{
	size_t fill;
	uint32_t left;

	if (ilen == 0) {
		return;
	}

	left = ctx->total[0] & 0x3F;
	fill = 64 - left;

	ctx->total[0] += (uint32_t)ilen;
	ctx->total[0] &= 0xFFFFFFFF;

	if (ctx->total[0] < (uint32_t)ilen) {
		ctx->total[1]++;
	}

	if (left && ilen >= fill) {
		memcpy((void *)(ctx->buffer + left), input, fill);
		mbedtls_sha256_process(ctx, ctx->buffer);
		input += fill;
		ilen -= fill;
		left = 0;
	}

	while (ilen >= 64) {
		mbedtls_sha256_process(ctx, input);
		input += 64;
		ilen -= 64;
	}

	if (ilen > 0) {
		memcpy((void *)(ctx->buffer + left), input, ilen);
	}
}

static const unsigned char sha256_padding[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/*
 * SHA-256 final digest
 */
void mbedtls_sha256_finish(mbedtls_sha256_context *ctx, unsigned char output[32])
{
	uint32_t last, padn;
	uint32_t high, low;
	unsigned char msglen[8];

	high = (ctx->total[0] >> 29)
		   | (ctx->total[1] << 3);
	low = (ctx->total[0] << 3);

	PUT_UINT32_BE(high, msglen, 0);
	PUT_UINT32_BE(low, msglen, 4);

	last = ctx->total[0] & 0x3F;
	padn = (last < 56) ? (56 - last) : (120 - last);

	mbedtls_sha256_update(ctx, sha256_padding, padn);
	mbedtls_sha256_update(ctx, msglen, 8);

	PUT_UINT32_BE(ctx->state[0], output, 0);
	PUT_UINT32_BE(ctx->state[1], output, 4);
	PUT_UINT32_BE(ctx->state[2], output, 8);
	PUT_UINT32_BE(ctx->state[3], output, 12);
	PUT_UINT32_BE(ctx->state[4], output, 16);
	PUT_UINT32_BE(ctx->state[5], output, 20);
	PUT_UINT32_BE(ctx->state[6], output, 24);

	if (ctx->is224 == 0) {
		PUT_UINT32_BE(ctx->state[7], output, 28);
	}
}

#endif							/* !MBEDTLS_SHA256_ALT */

/*
 * output = SHA-256( input buffer )
 */
void mbedtls_sha256(const unsigned char *input, size_t ilen, unsigned char output[32], int is224)
{
	mbedtls_sha256_context ctx;

	mbedtls_sha256_init(&ctx);
	mbedtls_sha256_starts(&ctx, is224);
	mbedtls_sha256_update(&ctx, input, ilen);
	mbedtls_sha256_finish(&ctx, output);
	mbedtls_sha256_free(&ctx);
}

#if defined(MBEDTLS_SELF_TEST)
/*
 * FIPS-180-2 test vectors
 */
static const unsigned char sha256_test_buf[3][57] = {
	{"abc"},
	{"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"},
	{""}
};

static const int sha256_test_buflen[3] = {
	3, 56, 1000
};

static const unsigned char sha256_test_sum[6][32] = {
	/*
	 * SHA-224 test vectors
	 */
	{
		0x23, 0x09, 0x7D, 0x22, 0x34, 0x05, 0xD8, 0x22,
		0x86, 0x42, 0xA4, 0x77, 0xBD, 0xA2, 0x55, 0xB3,
		0x2A, 0xAD, 0xBC, 0xE4, 0xBD, 0xA0, 0xB3, 0xF7,
		0xE3, 0x6C, 0x9D, 0xA7
	},
	{
		0x75, 0x38, 0x8B, 0x16, 0x51, 0x27, 0x76, 0xCC,
		0x5D, 0xBA, 0x5D, 0xA1, 0xFD, 0x89, 0x01, 0x50,
		0xB0, 0xC6, 0x45, 0x5C, 0xB4, 0xF5, 0x8B, 0x19,
		0x52, 0x52, 0x25, 0x25
	},
	{
		0x20, 0x79, 0x46, 0x55, 0x98, 0x0C, 0x91, 0xD8,
		0xBB, 0xB4, 0xC1, 0xEA, 0x97, 0x61, 0x8A, 0x4B,
		0xF0, 0x3F, 0x42, 0x58, 0x19, 0x48, 0xB2, 0xEE,
		0x4E, 0xE7, 0xAD, 0x67
	},

	/*
	 * SHA-256 test vectors
	 */
	{
		0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA,
		0x41, 0x41, 0x40, 0xDE, 0x5D, 0xAE, 0x22, 0x23,
		0xB0, 0x03, 0x61, 0xA3, 0x96, 0x17, 0x7A, 0x9C,
		0xB4, 0x10, 0xFF, 0x61, 0xF2, 0x00, 0x15, 0xAD
	},
	{
		0x24, 0x8D, 0x6A, 0x61, 0xD2, 0x06, 0x38, 0xB8,
		0xE5, 0xC0, 0x26, 0x93, 0x0C, 0x3E, 0x60, 0x39,
		0xA3, 0x3C, 0xE4, 0x59, 0x64, 0xFF, 0x21, 0x67,
		0xF6, 0xEC, 0xED, 0xD4, 0x19, 0xDB, 0x06, 0xC1
	},
	{
		0xCD, 0xC7, 0x6E, 0x5C, 0x99, 0x14, 0xFB, 0x92,
		0x81, 0xA1, 0xC7, 0xE2, 0x84, 0xD7, 0x3E, 0x67,
		0xF1, 0x80, 0x9A, 0x48, 0xA4, 0x97, 0x20, 0x0E,
		0x04, 0x6D, 0x39, 0xCC, 0xC7, 0x11, 0x2C, 0xD0
	}
};

/*
 * Checkup routine
 */
int mbedtls_sha256_self_test(int verbose)
{
	int i, j, k, buflen, ret = 0;
	unsigned char *buf;
	unsigned char sha256sum[32];
	mbedtls_sha256_context ctx;

	buf = mbedtls_calloc(1024, sizeof(unsigned char));
	if (NULL == buf) {
		if (verbose != 0) {
			mbedtls_printf("Buffer allocation failed\n");
		}

		return (1);
	}

	mbedtls_sha256_init(&ctx);

	for (i = 0; i < 6; i++) {
		j = i % 3;
		k = i < 3;

		if (verbose != 0) {
			mbedtls_printf("  SHA-%d test #%d: ", 256 - k * 32, j + 1);
		}

		mbedtls_sha256_starts(&ctx, k);

		if (j == 2) {
			memset(buf, 'a', buflen = 1000);

			for (j = 0; j < 1000; j++) {
				mbedtls_sha256_update(&ctx, buf, buflen);
			}
		} else {
			mbedtls_sha256_update(&ctx, sha256_test_buf[j], sha256_test_buflen[j]);
		}

		mbedtls_sha256_finish(&ctx, sha256sum);

		if (memcmp(sha256sum, sha256_test_sum[i], 32 - k * 4) != 0) {
			if (verbose != 0) {
				mbedtls_printf("failed\n");
			}

			ret = 1;
			goto exit;
		}

		if (verbose != 0) {
			mbedtls_printf("passed\n");
		}
	}

	if (verbose != 0) {
		mbedtls_printf("\n");
	}

exit:
	mbedtls_sha256_free(&ctx);
	mbedtls_free(buf);

	return (ret);
}

#endif							/* MBEDTLS_SELF_TEST */

#endif							/* MBEDTLS_SHA256_C */
